A device for adjusting the temperature of superheated reheated steam with water as a cooling medium, its function is to control and maintain the temperature of the superheated steam or the reheated steam to a specified value, and to prevent the superheater and the reheater tube wall from being heated. The desuperheater is divided into two types: surface type and water spray type.
Surface desuperheater: It is a tubular heat exchanger that uses feed water or furnace water to cool steam. Cooling water flows in the tubes, steam flows between the tubes, and flushes the outer walls of the tubes to release heat, thereby cooling. The desuperheater uses the method of adjusting the amount of cooling water to change the heat absorption of the cooling water to achieve the purpose of adjusting the temperature of the steam. According to the structure of the surface desuperheater, it can be divided into two types: U-shaped tube (or coiled incense tube) type and casing type. The advantage of surface desuperheater is that water and water vapor are not in direct contact, and there is no special requirement for water quality. The disadvantage is that the structure is complex, the heating surface is large, and the inertia (delay) of temperature regulation is large. It is generally used in low and medium-pressure boilers.
Water spray desuperheater: A device that directly sprays atomized cooling water into the temperature-regulated water vapor to evaporate it into water vapor and mix well with the temperature-regulated water vapor to reduce the temperature of the temperature-regulated water vapor
The spray desuperheater can be divided into Venturi type, vortex type, and multi-hole nozzle type according to the structure of cooling water sprayed into temperature-regulated water vapor. The principle is to cool part of the saturated steam with feed water into condensed water and spray it into the desuperheater to adjust the temperature. The water injection relies on the pressure difference between the condenser and the desuperheater, and no special desuperheating pump is required. The characteristics of the water spray desuperheater are simple structure, large temperature adjustment range (up to 50 ° C - 65 ° C), sensitive temperature adjustment, and easy to achieve automation. Therefore, it is widely used in boilers. The disadvantage is that it has high requirements for water spray quality.